Production of cellulose derivatives



Patented July 10, 1945 I PRODUCTION OF CELLULOSE DERIVATIVES Henry Dreyfus London, England, assignor to Cel anese Corporation of America, a corporation of Delaware No Drawing. Application May 20, 1942, Serial No. 443,806. In Great Britain May 16, 1941 11 Claims. (Cl. s' 116.2)

Thi invention is concerned with improvements in or relating tothe production of cellulose derivatives.

According to the present invention the properties of cellulose materials are improved by reacting them with organic dicyanamides, i. e..com-- pounds containing two radicles having the formula:

The treatment with dicyanarnides results in an improvement in the physical properties of the materials. In particular, the safe ironing temperature and melting point of materials" made of organic acid esters and vethers of cellulose may be improved and the solubility of the materials in organic solvents may be reduced. The

lulose materials obtained by the viscose or cuprammonium process or by the saponification of cellulose acetate or other organic ester of cellulose, or materials made of an organic derivative of cellulose containing free hydroxy groups.-

For instance, the process may be applied to' the treatment of yarns of high tenacity in hank or fabric form obtained by the stretching of acetonesoluble cellulose acetate, for example to or times its original length in wet steam or hot water under pressure, or to'yarns of regenerated cellulose made by the saponification of the above stretched cellulose acetate yarns. The yarns may be of ordinary viscosity or the high viscosity yarns produced as described in U. S. Application S. No. 400,122, filed June 27, 1941.

Examples of cyanamides which may be employed are those compounds containing two radicles of the formulae and those compounds having the formulae: NC.NH.(CH2)1n- NH.CN where n is an integer,

integer and X is a xii-,valent non-metallic. atom, and

RINK-0N BmncN where R is an aromatic residue and R1 and R2 are alkylene radicles, more specifically ethylene and hexamethylene dicyanamides, beta,beta dicyanamido-diethyl ether, beta,bet a di-cyanamido-diethyl sulphide and di(beta-cyanamidoethyl) benzenes, They may be produced as described, for example in No. 2,349,851.

The reactions may be efiected by heating the materials in a solution of a dicyanamide. Preferably a fairly dilute solution containing, for example 2.5% of di-cyanamide, is employed and the reaction temperature is between 50 and 150 C., particularly 100 to 120 C.

Cellulosic materials may be treated with a solution which contains the dicyanamide and which is a solvent for the materials if alteration of their physical state is immaterial. For instance, cellulose acetate in fibrous or'powder form may be'refiuxed with a solution of a dicyanamide in acetone and on completion of the reaction may be precipitated by the addition of a non-solvent or separated from the reaction medium if the reaction has been carried sufficiently far to tender it insoluble therein As indicated above, however, the present pn ess is of most value for the treatment of artificial filaments, foils and other shaped articles and in such a case should be carried out with a reaction medium which does not deleteriously aiiect their physical condition.

Such a process is preferably efiected by impregnating the articles with a solution of the dicyanamide in a volatile solvent, e. g., alcohol, acetone or chloroform, concentrating the di-cyanamide on the material by evaporation of the volatile solvent and then heating the impregnated articles until the required reaction has taken place, which usually necessitates about 15 mins. to 1 hour at a temperature of 100-120 C. Usually a fairly low proportion of dicyanamide to cellulosic materials is suflicient to give the imcentration may be used andthe impregnated material subsequently hydro-extracted or otherwise treated so as to reduce its content or impregnating medium to the required amount before the volatile solvent is evaporated oil.

The following examples areglven to illustrate the invention.-

. Example 1 A fabric made of regenerated cellulose is immersed in a 2% solution of hexamethylene dicyanamide in acetone at 40 C. for about minutes and is then withdrawn and hydro-extracted until it retains about its own weight, of liquor. It is then heated for half an hour at 110 C. under such conditions that the acetone can evaporate, after which it is scoured and dried.

Example 2 A cellulose acetate fabric made of cellulose acetate yarn which has been stretched in wet steam to about 10 times its original length, is reacted with hexamethylene dicyanamide in a similar manner to that described in Example 1, using a solution of the dicyanamide in alcohol.

Having described my invention what I desire to secure by Letters Patent is:

1. Process for the treatment of cellulosic materials which comprises reacting them with an organic compound containing two radicles having the formula:

2. Process for the treatment of cellulosic illae ments, foils and similar materials, which comprises reacting them with an organic compound containing two radicles having the formula:

3. Process for the treatment of filaments, foils and similar materials having a basis of regenerated cellulose, which comprises reacting them with an organic compound containing two radicles having the formula:

4. Process for the treatment of filaments, foils and similar materials having, a. basis of cellulose acetate, which comprises reacting them with an organic compound containing two radicles having the formula: I

5. Process for the treatment of cellulosic materials, which comprises impregnating the materials with a dilute solution of an organic compound containing two radicles having the formula: -CH2.NH.CN and heating the impregnated materials to a temperature between 50 and 150 C.

6. Process for the treatment of cellulosic materials, which comprises impregnating thematerials with a 1 to 5% solution of an organic compound having the formula:-

ncnnxcrmmnncn where n is an integer and X is a di-valent nonmetallic atom, and heating the impregnated materials to a temperature between and C.

9. Process for the treatment of cellulosic materials, which comprises impregnating the materials with a 1 to 5% solution of an organic compound having the formula:

where R is an aromatic residue and R1 and R2 are alkylene radicles and heating the impregnated materials to a temperature between 100 and 120 C.

10.,Process for the treatment of shaped cellulosic materials, which comprises impregnating the materials with a dilute solution of an organic compound containing two radicles having the formula:

in a liquid which is a non-solvent for the cellulosic materials, and heatin the impregnated materials to a temperature between 50 and C.

11. Process for the treatment of shaped cellu lose acetate materials, which comprises impregnating the materials with a 1 to 5% solution of an organic compound having the formula:

in ethyl alcohol and heating the impregnated materials to a temperature between 100 and 120 C.

' HENRY DREYF'US. 

